On Tue, Apr 13, 2021 at 3:37 AM Jeff Gostick <jgost...@gmail.com> wrote:
> It is great to hear that this might be useful. I would LOVE to create a > PR on this idea and contribute back to numpy...but let's not get ahead of > ourselves :-) > > Regarding the name, I kinda like "unpad" since it relates directly to > "pad", analogous to "ravel" and "unravel" for instance. Or maybe "depad". > Although, it's possible to use this on any array, not just a previously > padded one, so maybe tying it too directly to "pad" is not right, in which > case "trim" and "crop" are both perfect. I must admit that I find it odd > that these functions are not in numpy already. I just searched the docs > and they show up as keyword args for a few functions but are otherwise > conspicuously absent. Also, funnily, there is a link to "padding arrays" > but it is basically empty: > https://numpy.org/doc/stable/reference/routines.padding.html. > > Alternatively, I don't hate the idea of passing negative pad widths into > "pad". I actually tried this at one point to see if there was a hidden > functionality there, to no avail. > > BTW, we just adding a custom "unpad" function to our PoreSpy package for > this purpose: > https://github.com/PMEAL/porespy/blob/dev/porespy/tools/_unpadfunc.py > > > > On Mon, Apr 12, 2021 at 9:15 PM Stephan Hoyer <sho...@gmail.com> wrote: > >> On Mon, Apr 12, 2021 at 5:12 PM Jeff Gostick <jgost...@gmail.com> wrote: >> >>> I guess I should have clarified that I was inquiring about proposing a >>> 'feature request'. The github site suggested I open a discussion on this >>> list first. There are several ways to effectively unpad an array as has >>> been pointed out, but they all require more than a little bit of thought >>> and care, are dependent on array shape, and honestly error prone. It would >>> be very valuable to me to have such a 'predefined' function, so I was >>> wondering if (a) I was unaware of some function that already does this and >>> (b) if I'm alone in thinking this would be useful. >>> >> >> Indeed, this is a fair question. >> >> Given that this is not entirely trivial to write correctly, I think it >> would be reasonable to add the inverse operation for pad() into NumPy. This >> is generally better than encouraging users to write their own thing. >> >> From a naming perspective, here are some possibilities: >> unpad >> trim >> crop >> >> I think "trim" would be pretty descriptive, probably slightly better than >> "unpad." >> > I'm not a fan of `trim`. We already have `clip` which sounds similar. `unpad` looks like the only one that's completely unambiguous. `crop` sounds like an image processing function, and what we don't want is something like Pillow's `crop(left, top, right, bottom)`. Cheers, Ralf _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@python.org >> https://mail.python.org/mailman/listinfo/numpy-discussion >> > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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